Reminder: There's also the possibility that one person in a gay couple will come out straight.
That disclosure is equally difficult for the partner who didn't know.
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In my case my first partner came out after 10 years together. I had no idea for most of our relationship. Toward the end he said he was bi, but then decided he was gay. He is now married to a man and they have two children from surrogates.
My second partner claimed all along to be bi, but said he wanted an exclusive relationship with me. He was a crossdresser but of course that doesn't mean he was necessarily gay. Within a couple of years he admitted he was gay. He was using me as a beard. I have no idea where he is now because he was an addict and very unstable.
My third partner was / is seemingly transgendered (male to female), crossdresses, and a year or two into our relationship he claimed he was bicurious. About a year later he came out as gay and now dates men exclusively. We are still best friends after twenty years.
I've started seeing someone new. Let's just say I'm a little cautious about getting hurt again.
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I never give you my number, I only give you my situation.
Beatles